A “tip” of the prior art includes components used to make an acoustic-mechanical connection with the ear of a patient for medical instruments that can sense and measure physiological parameters of the human ear. A pliable silicone or plastic tip having a flexible surface, such as a flexible seal, can be seated against the outer surface of the auditory canal for acoustic measurements. The tip can provide both an acoustic interface to the auditory canal as well as a pneumatic pressure seal. The properties of the acoustic interface should be compatible with the frequency or tone of test signals being used.
In the field of tympanometry, an example of a field that relates to acoustic measurements of the ear, a medical instrument typically measures the impedance or admittance of the ear canal/tympanic membrane/middle ear system. To make a tympanometric measurement, an audio signal is first transmitted into the auditory canal, generally by an acoustic transmitter, such as a small speaker in the tympanometric instrument while a small microphone in the instrument simultaneously monitors sound in the auditory canal. This process is continued while varying the static pressure inside the ear canal, typically using a pump or similar means. The instrument can thus measure the changing impedance or admittance of the ear system as a function of pressure. The results of such measurements, indicating mobility of the tympanic membrane and ossicular chain, can be helpful to clinicians in assessing and diagnosing various conditions and pathologies of the ear.
By convention and standards, tympanometric measurements have generally been performed at a fixed frequency of about 226 Hz. Various forms of tympanometric instruments and tips have been commonly used. Based on relatively recent research, there is a move in the industry towards using 1,000 Hz as the new standard frequency, especially for infants & patients under 6 months of age.
For prior art devices that currently use a 226 Hz probe tone, a direct conversion or upgrade to a 1000 Hz probe tone can create problems with instrument accuracy.
What is needed, therefore, is an acoustic-mechanical tip for a medical instrument that can provide accurate acoustic-physiological measurements using audio frequencies of 1,000 Hz or greater.